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Vol. XXVII No. 3, May 16-31, 2017

Sewage proves beastly in the City

by A Special Correspondent

What use such beauty at the Chetput Eco Park when sewage is such a beast in the city?What use such beauty at the Chetput Eco Park (see here) when sewage is such a beast in the city?

Recent reports of sewage-laden lorries raising a stink and the load being discharged into stormwater channels are disturbing. Sewage is removed and transported because the city’s underground sewage network capacity is inadequate to cope with the existing load. The stench of rotting garbage is a sign of a brewing scam in Koyambedu where, it is reported, the contract for daily removal of 200 tons of biowaste has not been honoured while bills are made and payments effected. Which one is easier for the poor citizen to bear – the stench of garbage or the stench of corruption?

Another recent report describes in harrowing detail the sufferings of the residents of a street in Vadapalani where frequent stagnation of sewage blocking the whole street has kept residents indoors, with windows and doors shut to avoid the stench and the breeding mosquitoes. Temporary reliefs from clogged pipelines, without solving the larger problem with a permanent solution, leads us nowhere. Hazardous attempts at clearing the clogged lines are fraught with risk of asphyxiation and loss of life has been frequently reported. We keep removing the toxic material and dumping it back into waterways and floodwater drains in a vicious cycle. These are signs of a primitive state of our waste water handling system.

Information on plans for the sewage management in the Chennai Metro area, as stated by the Chennai Metro Water Supply and Sewage Board (CMWSSB), does not inspire confidence that the government is focused on the magnitude of this problem. The ‘Master Plan’ speaks of improvement to sewage collection and conveyance system (emphasis mine) in the City, which implies that physical collection and conveyance is substituting for the inadequate capacity of the underground pipeline network. This is treatment of the symptom instead of the malaise. The Board also states that the treatment capacity has been raised from 222 million litres per day (MLD) in 1991 to 486 MLD. Urban population has also been growing during this period from 2.5-3% per year, mainly through in-migration. The metro area remaining the same, the increasing density puts an additional the load on the system.

Significantly, the Board does not state the daily rate of waste generation in the metro area to be able to verify if the installed capacity of 486 MLD is sufficient. To arrive at the effective capacity, it is customary and prudent to de-rate the installed capacity by a minimum of 10 per cent for maintenance and unavoidable breakdowns causing loss of production time. On this basis, the effectively available capacity is only 437 MLD.

In 2015, the estimated sewage generation in the country was 61,754 MLD as against the sewage treatment capacity of 22,963 MLD (according to the International Institute of Health and Hygiene, New Delhi, a Ministry of Environment, Forests and Climate Change body). Tamil Nadu is one of five States that account for approximately 50 per cent of the total sewage generated in the country. Based on this it would be reasonable to assume the rate of waste generation in Tamil Nadu to be 6,000 MLD. Chennai Metro’s population is 11.25 per cent of the State population and as such the share of Chennai Metro could be around 11.25 per cent of 6,000 MLD i.e. 675 MLD against the available effective treatment capacity of 437 MLD. The available capacity does seem far below the waste generated by the City every day, necessitating haphazard dumping of untreated sewage of large volumes.

Upgrading a city’s sewage system involves extensive work; apart from a modern sewage facility of sufficient combined capacity to meet the growing needs for the next fifty years or so. Matching capacity of infrastructure is needed to collect wastewater. In European countries, most of the money spent on wastewater treatment is invested in designing and building systems for wastewater collection – which refers to the sewage drainage underground network in our case. Singapore is setting up a deep tunnel sewage system that provides for laying two 80 km long, 6.5metre-wide tunnels placed 50 metres below ground level to carry sewage from feeder lines by gravity to the treatment plants. In Israel, about 50 percent of agricultural water use is provided through reclaimed sewer water. Arab countries with scarce water employ similar treated and recycled usage of waste water and keep their public places adorned with lawns and flower beds, as, for instance, in Abu Dhabi.

Handling wastewater sewage and treating it for final re-use or disposal in harmless form is a mammoth task and the biggest challenge that cities face everywhere and especially so in developing countries. With a possibility of water becoming a scarce resource, globally, we cannot afford for long to squander away much water to wash our waste and let it become a breeding base for squalor and disease. The Smart City funds provided by the Centre should be utilised for this urgent public health challenge which, by its criticality, can easily win the priority contest. Funds for such projects would also be available from multi-lateral finance institutions provided we put in our share which can be released by cutting out vote-seeking freebies.

Till a comprehensive sewage management project, using latest technology, that would stand good for several decades is conceived and executed, money and effort spent on river front and beach beautification and similar schemes of cosmetic nature smack of a basic misunderstanding of priorities. Chennai is naturally well-endowed and a beautification scheme can wait for its turn. What citizens want more is a safe and healthy sewage disposal project. Beauty needs to be rescued from the Beast.

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